1. Field of the Invention
The present invention relates to an apparatus for producing an organic EL display device, and a process for producing an organic EL display device. More specifically, the present invention relates to a producing apparatus making it possible to produce an organic EL display device capable of suppressing the generation of non-luminescence areas or non-luminescence spots, which may be referred to dark spots, in pixels; and a process for producing such an organic EL display device.
The xe2x80x9cELxe2x80x9d described in the claims and the specification is an abbreviation of xe2x80x9celectroluminescencexe2x80x9d.
2. Description of the Related Art
Hitherto, various sealing means and moisture-proof means in organic EL display devices have been investigated to exclude the effect of moisture in the atmosphere and suppress the generation of non-luminescence areas, non-luminescence spots and the like in luminescence areas at the time of driving the devices.
It is also studied that an organic EL display device is produced without being exposed to the atmosphere. Such a producing apparatus is disclosed in JP-A-No. 8-111285, 10-214682 or 10-335061.
As illustrated in FIG. 20, in a producing apparatus 250 for an organic EL display device disclosed in JP-A-No. 8-111285, plural vacuum chambers 111 to 116 for working are connected to the periphery of a vacuum device 110. A movable arm 102 for carriage is disposed inside the vacuum device. Thus, a substrate 104 can be moved while the vacuum device and the working vacuum chambers are under a reduced pressure condition.
Therefore, respective layers of an organic EL element can be formed on the substrate in the respective working vacuum chambers while the substrate is passed through the single vacuum device. In other words, an organic EL display device can be produced without being exposed to the atmosphere from the respective film-depositing step to the step of forming a protective film.
As illustrated in FIG. 21, an apparatus for producing an organic EL display device disclosed in JP-A-No. 10-214682 comprises independent 1 st-nth working vacuum chambers 222a to 226a, and 1 st-nth carrying vacuum chambers 222 to 226 connected to the working vacuum chambers through gate valves 222d to 226d, respectively. The carrying vacuum chambers 222 to 226 are horizontally connected to each other through gate valves 222c to 227c. A substrate and so on can be transferred from a first dry box 221, which is an inlet, to a second dry box 227, which is an outlet, by means of robot arms 222b to 226b set up in the respective carrying vacuum chambers.
Accordingly, it is possible that respective layers of an organic EL element are formed in the respective working vacuum chambers and the unfinished organic EL element can be successively moved in the respective working vacuum chambers through the carrying vacuum chambers while the working vacuum chambers are in a reduced pressure state. In short, an organic EL display device can be produced without being exposed to the atmosphere from the step of depositing its films to a sealing step.
As illustrated in FIG. 22, an apparatus for producing an organic EL display device, disclosed in JP-A-No. 10-335061, comprises a vacuum chamber 315, a vacuum device 307 connected to the vacuum chamber, a carrying and pressing means 316 for carrying an organic EL element 309 or a sealing member 312 in the vacuum chamber, a hardening means 311 for hardening an adhesive layer 313 between the organic EL element 309 and the sealing member 312.
It is therefore possible to form respective layers of the organic EL element inside the vacuum chamber 315 and further harden the adhesive layer 313 with the hardening means (ultraviolet-ray exposure device) 311 in the state that the sealing member 312 prepared inside the vacuum chamber is positioned and then pressed from the above by means of the carrying and pressing means 316. In short, an organic EL display device can be produced without being exposed to the atmosphere from the step of depositing its films to a sealing step.
However, in the organic EL display device producing apparatus disclosed in JP-A-No. 8-111285, the number of the working vacuum chambers (vapor-depositing chambers or sputtering chambers) arranged around its vacuum tank is as large as, for example, five. Thus, a problem that the producing apparatus becomes large-sized arises.
No unit for removing water from an organic EL wafer wherein a transparent element, an organic film and so on are formed on a glass substrate is set up. It is therefore difficult to lower the water content in an organic luminescence medium in the resultant organic EL display device. Thus, a problem that dark spots as non-luminescence areas are easily generated arises.
A problem that sealing is insufficient is also caused since a protective film is formed on the organic EL wafer and subsequently the resultant is exposed to the air.
The organic EL display device producing apparatus disclosed in JP-A-No. 10-214682 comprises the 1 st-nth working vacuum chambers, the 1 st-nth carrying vacuum chambers and the first and second dry boxes, and they are horizontally connected to each other. Thus, this apparatus has a problem that it becomes markedly large-size.
This producing apparatus has the first dry box. However, the first dry box is a space where the water content is controlled into a low value and no heating device is set up. Thus, water contained in a substrate and so on cannot be positively removed.
Therefore, it is difficult to lower the water content in the organic luminescence medium in the resultant organic EL display device. Thus, it has still been difficult to suppress the generation of dark spots and so on as non-luminescence areas and obtain a high luminescence brightness for a long time.
The organic EL display device producing apparatus disclosed in JP-A-No. 10-335061 has no water-removing means, that is, no function for removing water contained in a substrate and so on positively. Therefore, it is difficult to lower the water content in the organic luminescence medium in the resultant organic EL display device. Thus, it has still been difficult to suppress the generation of dark spots and so on as non-luminescence areas and obtain a high luminescence brightness for a long time.
As illustrated in FIG. 23, an organic EL display device producing apparatus 400 disclosed in JP-A-No. 2000-133446 comprises load side receipt chambers 412 and 413, a load side normal-pressure carrying chamber 411, a load chamber 421, a vacuum carrying chamber 431, film-depositing chambers 432 to 435, an unload chamber 441, an unload side normal-pressure carrying chamber 451, unload side receipt chambers 452 and 453, and an airtight working chamber 454, and is characterized in that an inert gas atmosphere having a water content of 100 ppm or less is filled at least into the unload chamber 441 and the unload side normal-pressure carrying chamber 451. JP-A-No. 2000-133446 also discloses that in the load side receipt chambers 412 and 413, a substrate and any organic material on the substrate are preferably heated to remove water from them.
However, in the disclosed organic EL display device producing apparatus, the position into which the substrate is carried and the position in which the substrate is heated are common. Therefore, the apparatus has a problem that in the case in which the load side receipt chamber is once heated, a next substrate cannot be carried thereinto until the temperature of the load side receipt chamber falls. Since the position into which a substrate is carried and the position in which the substrate is heated are common and further the load side normal-pressure carrying chamber is arranged after the heated load side receipt chamber, it is difficult to reduce the pressure of the load side receipt chamber, cool the chamber, or set up a precision balance therein. Therefore, a problem that it takes much time to remove water from the substrate and so on sufficiently or carry out a dehydration step arises.
Thus, it is suggested that plural load side receipt chambers are disposed. However, there arise problems that the whole of the producing apparatus including a heating device and a precision balance becomes large-scaled and the performances of resultant organic EL display devices are scattered because of a scattering in heating temperatures in the load-side receipt chambers.
Furthermore, in the disclosed organic EL display device producing apparatuses, the position into which a substrate is carried and the position in which the substrate is heated are common. Therefore, it is impossible that the position where the substrate is heated and the position where the substrate is cleaned are conversely made common. Thus, the apparatuses have problems that the whole of the apparatuses increasingly becomes large-scaled and further the substrate absorbs water at the time of the transfer of the substrate from the substrate-heating position to the substrate-cleaning device so that dehydration effect is lowered.
Thus, the inventors eagerly made further investigations on such problems. As a result, it has been found that by setting up a water-removing unit separately from the position into which a supporting substrate is carried and removing water positively from the substrate and so on through heating treatment, the water content in an organic luminescence medium can be markedly lowered, so that the generation of dark spots and the like, as non-luminescence areas, around pixels can be greatly suppressed.
Therefore, an object of the present invention is to provide an organic EL display device producing apparatus making it possible to obtain effectively an organic EL display device capable of suppressing the generation of dark spots and the like even if the device is driven for a long time.
Another object of the present invention is to provide an organic EL display device producing process making it possible to obtain effectively an organic EL display device capable of suppressing the generation of dark spots and the like even if the device is driven for a long time.
[1] According to the present invention, provided is an apparatus for producing an organic EL display device which has at least a lower electrode, an organic luminescence medium and an upper electrode, on the supporting substrate, and the periphery of the device being sealed with a sealing member,
the apparatus comprising:
a first unit for carrying the supporting substrate in,
a second unit for heating at least the supporting substrate before forming the organic luminescence medium, thereby conducting a dehydration treatment,
a third unit for forming the organic luminescence medium and the upper electrode, and
a fourth unit for sealing the periphery with the sealing member, and
carrying units being set up between the respective units. Thus, the above-mentioned problems can be solved.
Namely, this producing apparatus is made to comprise the second unit for conducting the dehydrating treatment positively, which is different from the location into which the substrate is carried. Therefore, the water content in the organic luminescence medium after the organic EL display device is fabricated is easily adjusted. Thus, it is possible to obtain easily the organic EL display device superior in endurance wherein the generation of dark spots and the like as non-luminescence areas is markedly reduced.
[2] In the organic EL display device producing apparatus of the present invention, it is preferred that the first unit is arranged between the second unit and the third unit.
According to this producing apparatus, the substrate and so on can be repeatedly reciprocated between the second unit and the third unit through the first unit. Therefore, film-deposition and dehydration can be repeated any number of times.
According to this producing apparatus, the first unit can function as a buffer at the time of the heating in the second unit and a reduction in the pressure in the third unit.
[3] In the organic EL display device producing apparatus of the present invention, it is preferred that the second unit is composed of a heating room and a cooling room.
This structure makes it possible to cool the substrate promptly in the cooling room even if the substrate is heated under a reduced-pressure in the heating room.
[4] In the organic EL display device producing apparatus of the present invention, it is preferred that the second unit is provided with at least one of an inert gas circulating device, a pressure-reducing device, and a cooling device.
This structure makes it possible to use the inert gas while the dehydrating treatment by heating is conducted. Therefore, the dehydrating treatment can be more effectively conducted in the state that the organic EL display device is not substantially exposed to the atmosphere.
This structure also makes it possible to conduct the dehydrating treatment by heating in a reduced pressure state. Therefore, the dehydrating treatment can be made more effective.
This structure also makes it possible to cool the substrate easily after the dehydrating treatment by heating. Therefore, the time until the substrate is transferred to the next step can be markedly reduced. In the case that the dehydrating treatment by heating is conducted in a reduced pressure state, natural cooling does not advance. Thus, this cooling device is a particularly effective means.
[5] In the organic EL display device producing apparatus of the present invention, it is preferred that the first unit is provided with at least one of an inert gas circulating device, a pressure-reducing device, and a cooling device.
This structure makes it possible to use the inert gas in the first unit. Thus, the substrate and so on are not exposed to the atmosphere when they are transferred or cooled.
This structure also makes it possible to make the first unit into a reduced pressured state. Therefore, the substrate and so on can be transferred to the third unit in a reduced pressure state.
This structure also makes it possible to cool easily the substrate in the first unit after the dehydrating treatment by heating in the second unit. Thus, the time until the substrate is transferred to the next step can be markedly reduced.
[6] In the organic EL display device producing apparatus of the present invention, it is preferred that the fourth unit is connected to the first unit.
This structure makes it possible to arrange the 1 st to 4 th units in a radiant state and make the first carrying unit in common with the second carrying unit. Thus, the producing apparatus can be made small.
[7] In the organic EL display device producing apparatus of the present invention, it is preferred that the second unit is made in common with the fourth unit.
This structure makes it possible to save spaces for the first and fourth units. Thus, the producing apparatus can be made smaller.
[8] In the organic EL display device producing apparatus of the present invention, it is preferred that the third unit is a vacuum evaporation device having plural evaporation sources for evaporating plural samples simultaneously or successively.
This structure makes it possible to form the respective layers of the organic EL element while a given vacuum state is kept. Therefore, the water content in the organic luminescence medium can easily be adjusted. Moreover, the producing apparatus can be made smaller than the case in which the third unit is composed of plural evaporation devices and so on.
In order to obtain the organic luminescence medium and so on that have a uniform thickness, the substrate and the plural evaporation sources are preferably rotated independently.
[9] In the organic EL display device producing apparatus of the present invention, it is preferred that the third unit comprises a buffer room, a vacuum evaporation device, and a sputtering device.
This structure makes it possible to select appropriately the method for depositing each of the layers of the organic EL element dependently on the kind of the material thereof.
Since the buffer room is set up, the vacuum evaporation device can be connected to the sputtering device through the buffer room. Therefore, the degree of vacuum in the respective rooms can easily be adjusted.
The use of this buffer room makes replacement of plural substrate possible. Therefore, it is easy to different substrates simultaneously in the vacuum evaporation device and the sputtering device.
[10] In the organic EL display device producing apparatus of the present invention, it is preferred that the third unit further comprises a plasma-cleaning device. This structure makes it possible to make the organic EL display device more minute and better in endurance.
[11] Another embodiment of the present invention is a process for producing an organic EL display device, using any one of the above-mentioned producing apparatuses, comprises the steps of:
carrying a supporting substrate into the first unit,
using the carrying device to transfer the carried-in supporting substrate from the first unit to the second unit,
heating the transferred supporting substrate in the second unit to conduct a dehydrating treatment,
using the carrying device to transfer the dehydrated supporting substrate from the second unit to the third unit,
forming an organic luminescence medium and an upper electrode in the third unit,
using the carrying device to transfer the supporting substrate on which the organic luminescence medium and the upper electrode are formed from the third unit to the fourth unit, and
sealing the periphery of the organic EL display device with a sealing member in the fourth unit.
This process makes it easy to adjust the water content in the organic luminescence medium after the organic EL display device is fabricated. It is therefore possible to obtain effectively the organic EL display device wherein the generation of dark spots and the like is markedly reduced.
[12] In the organic EL display device producing process of the present invention, it is preferred that the second unit comprises a heating room and a cooling room, the supporting substrate is heated in the heating room to conduct a dehydrating treatment, and the dehydrated supporting substrate is cooled in the cooling room.
The process makes it possible to cool the substrate easily in the cooling room of the second unit even if the substrate is heated and dehydrated in a reduced pressure state in the heating room of the second unit. Thus, the time for producing the organic EL display device can be made short.
[13] A further embodiment of the present invention is a process for producing an organic EL display device, using the above-mentioned producing apparatus, comprises the steps of:
carrying a supporting substrate into the first unit,
using the carrying device to transfer the carried-in supporting substrate from the first unit to the second unit,
heating the transferred supporting substrate in the second unit to conduct a dehydrating treatment,
using the carrying device to transfer the dehydrated supporting substrate from the second unit to the third unit through the first unit,
forming an organic luminescence medium and an upper electrode in the third unit,
using the carrying device to transfer the supporting substrate on which the organic luminescence medium and the upper electrode are formed from the third unit to the fourth unit, and
sealing the periphery of the organic EL display device with a sealing member in the fourth unit.
Since there is used the producing apparatus wherein the place which the supporting substrate is carried into and the place which the substrate is dehydrated are different from each other, the producing time can be made short. Moreover, the flexibility of the arrangement of the producing apparatus is improved. Furthermore, the water content in the organic luminescence medium can easily be adjusted.
[14] A still further embodiment of the present invention is a process for producing an organic EL display device, using the above-mentioned producing apparatus, comprises the steps of:
carrying a supporting substrate into the first unit,
using the carrying device to transfer the carried-in supporting substrate from the first unit to the second unit,
heating the transferred supporting substrate in the second unit to conduct a dehydrating treatment,
using the carrying device to transfer the dehydrated supporting substrate from the second unit to the third unit through the first unit,
forming an organic luminescence medium and an upper electrode in the third unit,
using the carrying device to transfer the supporting substrate on which the organic luminescence medium and the upper electrode are formed from the third unit to the fourth unit via the first unit, and
sealing the periphery of the organic EL display device with a sealing member in the fourth unit.
This process makes it possible to make the producing time short, improve the flexibility of the arrangement of the producing apparatus, and make the adjustment of the water content in the organic luminescence medium easy.
[15] An additional embodiment of the present invention is a process for producing an organic EL display device, using the above-mentioned producing apparatus, comprises the steps of:
carrying a supporting substrate into the first unit,
using the carrying device to transfer the carried-in supporting substrate from the first unit to the second unit,
heating the transferred supporting substrate in the second unit to conduct a dehydrating treatment,
using the carrying device to transfer the dehydrated supporting substrate from the second unit to the third unit,
forming an organic luminescence medium and an upper electrode in the third unit,
using the carrying device to transfer the supporting substrate on which the organic luminescence medium and the upper electrode are formed from the third unit to the fourth unit which is in common with the second unit through the first unit, and
sealing the periphery of the organic EL display device with a sealing member in the fourth unit.
This process makes it possible to make the producing time short, improve the flexibility of the arrangement of the producing apparatus, and make the adjustment of the water content in the organic luminescence medium easy.
[16] In the organic EL display device producing process of the present invention, it is preferred that the supporting substrate dehydrated in the second unit is transferred to the first unit and cooled, and subsequently the supporting substrate is transferred to the third unit.
The cooling in the first unit in this way makes it possible to cool the supporting substrate effectively even if the substrate is dehydrated in a reduced pressured state in the second unit. Thus, the time until the substrate is transferred to the third unit can be shortened.
The cooling of the substrate dehydrated in the first unit makes it possible to dehydrate another substrate simultaneously in the second unit. Thus, productive efficiency can be improved.
[17] In the organic EL display device producing process of the present invention, it is preferred that the organic luminescence medium is formed in the third unit; the supporting substrate on which the organic luminescence medium is formed is then transferred to the second unit to conduct the dehydrating treatment; and subsequently the supporting substrate is again transferred to the third unit to form the upper electrode.
This process makes it easier to adjust the water content in the organic luminescence medium after the organic EL display device is fabricated. It is therefore possible to obtain effectively the organic EL display device wherein the generation of dark spots and the like is markedly reduced.
[18] In the organic EL display device producing process of the present invention, it is preferred that the water content in the organic luminescence medium after the sealing with sealing member is performed is set to 0.05% or less by weight.
This process makes it possible to obtain effectively the organic EL display device wherein the generation of dark spots and the like is markedly reduced under the storage not only at room temperature but also at a high temperature (for example, 80xc2x0 C.).